【动态规划】买卖股票的最佳时机Ⅲ

题目链接：https://leetcode.cn/problems/best-time-to-buy-and-sell-stock-iii/description/

classSolution{public:constintINF=0x3f3f3f3f;intmaxProfit(vector<int>&prices){/*时空复杂度O(n)*/intn=prices.size();// 1. 创建dp表vector<vector<int>>f(n,vector<int>(3,-INF));autog=f;// 2. 初始化f[0][0]=-prices[0],g[0][0]=0;// 3. 填表for(inti=1;i<n;++i)for(intj=0;j<3;++j){f[i][j]=max(f[i-1][j],g[i-1][j]-prices[i]);g[i][j]=g[i-1][j];if(j>=1)g[i][j]=max(g[i-1][j],f[i-1][j-1]+prices[i]);}// 4. 返回值// return max(g[n - 1][0], max(g[n - 1][1], g[n - 1][2]));intret=0;for(intj=0;j<3;++j)ret=max(ret,g[n-1][j]);returnret;}};